Really nice game
I liked the cheat idea and the hinting at the cheat without really revealing it.
Just two little things:
1. The speed you give the ball is very much, so you only want to have a very short sling/shotline, otherwise the planet gravity doesn't really have an impact. This makes it a bit unstable or unprecise especially when used for cheating. So maybe throttling the speed a bit would be nice.
2. Sometimes the planet gravity accelerates the ball also in the direction away from it, which seems a bit weird.
All in all it was really fun to play.